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rakker16mm
04-17-2008, 07:09 PM
http://www.atheenscreativecrafts.com/Painting/Camera_obscura_1.jpg

Please forgive the following verbosity.

Sometimes as artists we choose to clime the mountain rather than just paint it. For the most part I am happy to fake climbing the mountain since I recognize that any artistic representation I make can never represent the mountain as it really is. Any painting, drawing or photograph of the mountain is merely a 2D representation of it, but no matter how skillfully rendered it is never the mountain itself. It may be said that a sculpture or 3D model of the mountain brings you a little closer to reality, but still these too are not the mountain. Never the less something compels us to try.

Having watched William Vaughan's tutorial "Creating a glass surface using the Dielectric Material Node" and also having a formal education as a photographer it seems only natural that my first experiment with the dielectric material node I would make a simple lens. I was favorably impressed enough with the result that a series of experiments soon followed. I played around with morph targets to change every parameter for a simple spherical lens. I still have many ideas that I have yet to try such as asphericals and anamorphic lenses, as well as just really strange shapes, and using all of these in front of the the camera in the way a traditional photographer might use filters or other lens attachments.

One of the things I noticed right away was the lack chromatic aberrations normally associated with the simple lens. For artistic reasons I actually wanted the chromatic aberration and was a little disappointed that it was missing however it occurred to me that that since I didn't have to deal with chromatic aberration I could actually model a simple lens that was in every respect superior to its real world counterpart....... BUT..... it seems I was wrong :( Because after building my virtual view camera I was very disappointed to find there was no image on the film plane. So sad.

I could fake it all with a spot light or by mapping and image, but for some reason I really want to make a virtual view camera. Is there any way to do this with Lightwave?

Jarno
04-17-2008, 11:14 PM
You'll need to use global illumination. Raytracing alone won't produce such projected images.

---JvdL---

rakker16mm
04-17-2008, 11:33 PM
Thank you Jarno,

I turned on GI but it didn't help. May be I am missing some setting or something. When I get back to my studio I will attach a zip of my scene


I was just reading about the advanced camera in the manual about generating a lens with a mesh, but the documentation is a bit on the thin side. I also did a search on the message board but I didn't come up with much.


The advanced camera is a multi-purpose camera. With
the advanced camera, you can recreate real cameras and
lenses. You can shift the lens distortion over time. Custom
lenses can be created by using a mesh object.


page 22 chapter 13 LightWave_v9-Layout_screen.pdf

rakker16mm
04-18-2008, 12:44 AM
I did find a couple of short videos by William Vaughan on using the advanced camera.

ftp://ftp.newtek.com/products/LightWave/Trial/Videos/ViewCam.mov

ftp://ftp.newtek.com/products/LightWave/Trial/Videos/ACT.mov

It is close to the direction I want to go but I guess I still want to do it the hard way, but if any one knows where some more tutorials are on the advanced camera please let me know.

PhantomPhish
04-18-2008, 12:51 AM
You could set up a node network on the film plane to raytrace rays at Null/Point located where the pinhole is?

PhantomPhish
04-18-2008, 12:59 AM
Is this what you want? I made a box with the pinhole centred on 0,0,0, select the box in the Item Info node when you get it into Layout.

rakker16mm
04-18-2008, 01:34 AM
Oh that's very cool and pretty close to the idea I have in mind. I will have to get up early and get out to the studio to check it out.

I all so have been looking at using the advanced camera in combination with the CCTV shader. It looks like there are a lot of ways to do this, and a lot of paths to explore some really interesting territory.

Thank you

Weepul
04-18-2008, 04:06 AM
Doing it with radiosity is very possible - I've done it. :D

You have to use Monte Carlo radiosity (with directional rays turned on, 9.3+).

The attached scene is out of date and the attached render was done in FPrime, but the scene (with tweaks) should still work...

rakker16mm
04-18-2008, 09:46 PM
Is this what you want? I made a box with the pinhole centred on 0,0,0, select the box in the Item Info node when you get it into Layout.

I gave it a try and the background inverted as expected but my foreground objects did not render on the film plane. I must be missing something basic here because I had the same problem with Weepuls scene. It rendered the HDR image and focus it on the film plane but again non of my models showed up. Is there some global or per item setting involved here? If you could attache a ZIP of your scene that would be really great.

Thank you.

j

rakker16mm
04-18-2008, 09:55 PM
Doing it with radiosity is very possible - I've done it. :D

You have to use Monte Carlo radiosity (with directional rays turned on, 9.3+).

The attached scene is out of date and the attached render was done in FPrime, but the scene (with tweaks) should still work...

Weepul, I tried your scene out. I had a lot more noise and than your render on FPrime, but I wasn't sure if it had to do with my settings for the HDR image or if it was that I was not using FPrime. I was able to focus the back ground image on the back of the box but none of the models I put in front of the lens rendered. I think I am missing something basic because I had the same problem with PhantomPhish's setup. There must be a global or per item setting I am missing.

Anyway your help is appreciated even though I can't quite pull this off just yet. If you think of anything els that might help let me know.

Thanks
J

UnCommonGrafx
04-19-2008, 07:01 AM
VERY COOL!!
Substitute one of your objects for the car it asks for; you may have to adjust the size of it.
As a photography teacher, this is gonna definitely make it into the class. As someone who wants them to buy ten copies of LW, this cross-discipline opportunity will be a great selling point.

rakker16mm
04-19-2008, 10:34 AM
Thank you UnCommonGrafx,

Hopefully I have enough time before heading down to my friends house this morning. Oddly enough I am making a pinhole camera in the real world as well. I am using the box from an iPhone and an old tin can. It will take 120 or 220 film and has a curved film plane. I haven't calculated the FOV but it is pretty wide.

Thanks again,

J

rikperni
04-19-2008, 11:21 AM
...
One of the things I noticed right away was the lack chromatic aberrations normally associated with the simple lens. For artistic reasons I actually wanted the chromatic aberration and was a little disappointed that it was missing...


If you want you can have cromatic abberrations, on the dielectric node, in the ADVANCED tab there is a parameter called DISPERSION, if you set it high enough you'll have what you're lokking for :)

BYE BYE RIK

Weepul
04-19-2008, 04:39 PM
Weepul, I tried your scene out. I had a lot more noise and than your render on FPrime, but I wasn't sure if it had to do with my settings for the HDR image or if it was that I was not using FPrime.
It's probably because I let the FPrime render cook for a long time to get rid of the noise. ;)


I was able to focus the back ground image on the back of the box but none of the models I put in front of the lens rendered. I think I am missing something basic because I had the same problem with PhantomPhish's setup. There must be a global or per item setting I am missing.
I don't really know what to tell you...it works here. You need for the object to be illuminated brightly enough to be able to see...you need Raytrace Refraction on and to be using Monte Carlo radiosity with Directional Rays turned on...the object needs to be able to be seen by rays and radiosity...pretty basic settings. The lens is focused at infinity, so the object needs to be large and distant to show well.

PhantomPhish
04-20-2008, 05:02 PM
I gave it a try and the background inverted as expected but my foreground objects did not render on the film plane. I must be missing something basic here because I had the same problem with Weepuls scene. It rendered the HDR image and focus it on the film plane but again non of my models showed up. Is there some global or per item setting involved here? If you could attache a ZIP of your scene that would be really great.

Thank you.

j

Just add this object to a scene and render, you can swap out the head for something else to test with. By jiggling the rays you could theoretically introduce chromatic abberation and DOF onto the filmplane...